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the importance of manual labour

How important is the manual assembly in a production cycle?
Leica has always stressed the importance of the manual component in the production and assembly of its products. There is evidently a strong connection with the romantic idea of a craftsman in a cottage industry who carefully and with upmost concentration produces the parts of the final product and with great feeling adjusts the components as long as is necessary to function smooth-less and for a long period. There are enough descriptions on the internet that support this kind of image building. And Leica is not the only company to stress its reliance on manual labour for the assurance of ultimate quality.
Report after report in the manufacturing industry indicates that this view is a myth. CNC machinery and robotics are capable of producing parts and systems with tighter tolerances than manual labour can accomplish. The integration of the computer in the workflow for control and quality checks has had more impact on the final quality than human inspection. Of course there are instances where the expertise of a craftsperson can override the decision made by a computer. A good example is the case where the computer advised the machinist at the machine center to use a certain amount of coolant combined with a speed of the tool, where the craftsman noted that this was a wrong combination. Experience is important and computers are not perfect!
We should however not over estimate the importance of the human operator. One of the critical elements in the Leica rangefinder camera is the accuracy of the focus, a combination between the moving components in the finder, the shape of the curve at the end of the lens when it moves forwards or backwards and the roller mechanism in the camera body. The adjustment of the rangefinder in the camera body is done independent from any lens. It is assumed that the lens has its own adjustments to ensure full compatibility with the body mechanism. In reality this assumption is not correct, as can be seen from the many complaints by users who note that one lens focusses correctly and another one does not.
In the conventional way the rangefinder is adjusted by an operator looking through the finder at a target. The adjustment is done manually by focusing physically at three distances. The conditions of the operator are important: fatigue, unattentivenes and experience play a role. The current method employs a computer that simulates the three distances and the operator has to adjust what is projected on the computer screen, independent of the physical conditions of the operator.
CNC machinery in general is able to produce parts with a consistency and accuracy that surpasses that of the human operator at a classical machine. The complex shapes of some current Leica aspherical lens surfaces could not be produced without computer controlled machinery.
The original Leica camera was a product with a large number of gears, couplings, mechanical linkages and mechanical brakes to function as a transport mechanism, a rewind mechanism, a shutter release and timing mechanism and so on. It was organically built up form a bare chassis and the workman had to know the function of every part and every mechanism to assemble all parts in the correct sequence and adjust the parts to function durably and accurately. in this process manual labour was required.
In the modern digital Leica camera body there is a sequence of combining subassemblies, often produced by other companies. The linkages between subassemblies are mainly electronic or computational and not mechanical. So the level of manual adjustments is limited or computer assisted. The alignment of the sensor surface with the front bayonet ring is computer controlled and computer assisted. In the traditional mechanical camera the guide rails of the film guide are machined with a certain tolerance and the bayonet ring has to be adjusted with distance rings to the correct position.
There are many more aspects in the manufacturing processes between the traditional way and the current way, but you get the idea. There are no technical or procedural aspects in any manufacturing process that indicate that the manual assembly is inherently superior to a semi- automated process. The only argument that makes sense is that the low number of products, made in relatively small product runs does not justify (financially and economically) the deployment of dedicated machinery.
A critical assessment of the value and importance of manual labour in a modern manufacturing process might be needed to get a good grasp of what is its role.

Turnover figures
In a previous message I gave turnover figures of the Leica Company. Here are more data.
The documents from the Bundesanzeiger give financial data for the ACM Projektentwicklung GmbH and for the Leica AG Wetzlar/Solms.
There are also the results of the Leica Geschäftsberichte Solms*
All fiscal years run from 1 April to 31 March. Not all figures are available.

Leica AG——Turnover——System-cameras+lenses
2000/2001*——158————————66 of which 50 M-system